Both the Progressive PT30C and PT50C (as well as their hard wired versions) turn off power to your rig when they detect a situation that is outside their set parameters. When the hazard is gone they reset and restore power. They also have a 2 1/2 minute delay before they pass power at every start up. This is important if you have a brief power outage that comes right back on. You don't want your a/c compressors to be re-energized immediately so this is another safety for your "stuff".
I absolutely will not plug in anywhere without my PT50C and I have a spare still in the box if my primary one ever has to go back to the factory for service/repaid/warranty. Yes, it has a lifetime warranty.
2006 GMC 2500HD CCSB 4x4 Duramax/Allison, Titan 52 gallon fuel tank, Prodigy Controller, B&W Companion Hitch
2010 Jayco Designer 35RLTS, Cummins/Onan RV QG 5500 EVAP, Progressive Industries EMS-PT50C, TST Systems 507 TPMS, RV Flex Armor Roof